34 I CARDIAC INTERVENTIONS TODAY I OCTOBER/NOVEMBER 2008

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Japanese operators are among the leading opera-

tors performing percutaneous coronary interven-

tion (PCI) for chronic total occlusion (CTO). The

reason for this is likely because Japanese operators

have been making continuous innovations and have

established new methodology in this field (eg, the

controlled antegrade and retrograde subintimal track-

ing [CART] technique). This article examines the stan-

dard Japanese techniques, including guidewire and

catheter selection.

CO RO N A RY A N G I O G R A P H Y F O R C TO P C I

To perform PCI for CTO, appropriate coronary

angiography (CAG) images must be taken. For exam-

ple, in a case of a CTO lesion in the right coronary

artery (RCA), angiograms focused on the occluded

portion must be taken. Generally, in cases of CTO in

the RCA, collaterals are often formed from the left

coronary artery (LCA). An angiography of the LCA

must consider the RCA as well as the LCA; otherwise,

a PCI for CTO cannot be performed (Figure 1).

Angiograms taken from various angles are also essen-

tial. Both the entrance and exit of the CTO must be

visualized on multiple planes, preferably perpendicu-

lar to each other. If possible, the CTO site should be

fixed in the center and visualized without panning

the table. Sometimes, certain “tricks” are necessary,

such as starting contralateral dye injection and wait-

ing until enough collateral flow is supplied before

taking angiograms by pressing the foot switch

(Figure 2).

CO R R E C T I N T E R P R E TAT I O N O F C AG

The next important step is to interpret the properly

acquired CAG images to confirm the entrance and exit

of the CTO and where the wire is to proceed between

these points. The occluded portion of a CTO lesion can-

not be visualized on CAG, but based on various pieces

of information, it is possible to anticipate the course of

the occluded vessel. Calcification and bridging collaterals

are good indicators to estimate the course of the vessel.

In many cases, the right channel is found in the occlud-

Standard Japanese CTO Technique

An step-by-step analysis of angiographic views, selection, and strategies for guidewire selection and use.

BY YASUSHI ASAKURA, MD

Figure 1. A case of CTO of the RCA (A). Angiography of the LCA in a case of CTO of the RCA (B). Due to panning to see the distal

side of the LCA, the distal side of the RCA cannot be observed. Angiography focused on the RCA.The exit of the CTO (arrow) is

clearly visible (C).

A B C

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ed portion. Often, microchannels are found in the vicini-

ty of the entrance and exit of the CTO. These channels

have to be differentiated from a bridging collateral. If a

side branch is found to originate from the channel, its

presence is a sign that the channel is likely to be the true

lumen (Figure 3).

In some cases, the true lumen exists like an island in

a river (Figure 2). Such an island does not necessarily

have a certain length. As shown in Figure 4, it may

merely be a remnant confluence area of two side

branches.

It goes without saying that PCI procedures per-

formed after obtaining such pieces of information

and those without them differ in their success rates.

Therefore, we perform thorough reading of the CAG

images before operation. First, we observe the

images repeatedly at normal speed. Then, we

observe all the frames one by one. We spend at least

more than half an hour—in many cases about 1

hour—for interpretation of CAG images.

CO N T R A L AT E R A L I N J E C T I O N

One difference among Japanese operators and

European and American operators is whether or not

to use contralateral angiography. Japanese operators

always perform contralateral angiography if it is nec-

essary to observe the distal side of the CTO. On the

contrary, I have experienced cases in Europe and the

US where PCI is performed without contralateral dye

injection (Figure 5). Performing a PCI procedure with-

out contralateral dye injection may result not only in

decreased success rates but may lead to serious com-

A B C

Figure 2. A case of CTO close to the ostium of the RCA (A).The exit of the CTO is located at the bifurcation of the posterolateral

branch and posterior descending branch (B). Starting dye injection before taking angiograms makes it possible to visualize the

mid-RCA via the right ventricular branch (C).

A B

Figure 3. CTO lesion in the proximal LAD (A).The channel indicated by the white arrows had the appearance of a bridging col-

lateral, and on the right anterior oblique caudal view, the true channel seemed to exist on the upper side, closer to the epicardi-

um (B). However, with a septal branch originating from this channel, it was likely to be the true lumen. In the present case, the

wire was first introduced to the epicardial side without success. After reading of the CAG for a second time, a soft wire was

advanced into this microchannel and revascularization was achieved successfully.

36 I CARDIAC INTERVENTIONS TODAY I OCTOBER/NOVEMBER 2008

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plications. The operators who will continue advancing

the balloon catheter or other devices would not

notice a perforation with the wire, and this would

result in massive bleeding and easily cause tampon-

ade.

Even with a contralateral angiography, it is some-

times not possible to obtain a sufficient view of the

distal side of the CTO. In such cases, it is necessary to

find a specific collateral channel. The most common

pattern is the conus branch connecting the left ante-

rior descending artery (LAD) and the RCA. Figure 6

shows a case of CTO at the ostium of the LAD. The

LAD is supplied with good collateral flow from the

RCA, but the exit of the CTO is not visualized. In this

case, dye was injected into the proximal LAD via the

conus branch, and to visualize the exit of the CTO,

selective angiography of the conus branch is neces-

sary. Sometimes, the distal part of the CTO in the

RCA is visualized via the conus branch (Figure 7). The

conus branch can originate from a different orifice

than the RCA, and in an angiography of the RCA, cau-

tion must be used not to overlook the collateral

channel. For angiography of this separate conus, an

internal mammary artery catheter is often appropri-

ate. In rare cases, there is a collateral route through

the atrial branch supplying the distal part of the RCA

(Figure 8). In any of these cases, it is difficult to hold

the catheter in place, and it is useful to have the

guidewire in place or to use a microcatheter for

angiography. If a microcatheter is used, as little as <1

mL of the contrast media is required. In many cases,

these collateral routes can be clearly visualized by the

multislice CT scan gaining increased recognition for

PCI for CTO in recent years.

C H O I C E A N D H A N D L I N G O F T H E

G U I D E W I R E

Decisive for success or failure of CTO PCI is whether

the guidewire can pass through the CTO lesion.

Therefore, the question of choice and maneuvering a

guidewire is of extreme importance. However, there is

no particular standard for selecting a guidewire. There

is no such guidewire with which any CTO lesion can be

crossed. Therefore, when choosing a guidewire to use,

the operator should use the one that he or she is most

used to. The X-treme (Asahi Intecc, Nagoya, Japan) is

the guidewire I use first in most cases of CTO. It does

not matter if you cannot see microchannels on angiog-

raphy because pathologically, CTO lesions have

microchannels in the occluded segment. The tapered-

tip X-treme is very good at tracing these channels. If a

microchannel is seen on angiography, the common

A B C D

A B C D

E

Figure 4. CTO at the ostial LAD (A).The exit of CTO is indicated by the arrow (B).The arrow indicates the point of confluence of

the RV branch and septal branch (C).The point of confluence was considered to be the LAD trunk so that the wire was

advanced aiming at this point (D).The wire crossed the lesion successfully (E).

Figure 5. CTO of the RCA (A). Although the RCA distal to the CTO lesion was not visualized, no contralateral dye injection was

performed. Unsuccessful PCI was associated with wire perforation and formation of a large hematoma (arrow) (B). Later, a sec-

ond attempt of PCI was made with contralateral dye injection (C). Revascularization was achieved successfully (D).

.014-inch wire with a plastic jacket is often most suited.

If the lesion cannot be crossed using such lubricous

wires, one should not hesitate to go on to the next

step. Once having entered the false lumen, it is unlikely

to find the true lumen with these wires. There is even

the risk of enlarging the subintimal space.

As the next choice of guidewire, I recommend the

Miracle series (Abbott Vascular, Santa Clara, CA).

When manipulating, never rotate the guidewire exces-

sively. It is recommended to repeat advancing and

retrieving the wire little by little. When retrieving the

guidewire, it is important to feel the magnitude of fric-

tion with your fingers. Depending on the lesion, nei-

ther too much nor too little friction is good.

Manipulation of the guidewire at the exit of the CTO

is also critical. Just before the guidewire penetrates the

distal end of the CTO, angiography from several angles

must be taken (Figure 9). If possible, this should be

done also immediately after perforation is completed.

The success rate of PCI depends very much on

whether such extra efforts are made. However, many

operators, including Japanese operators, fail to make

these efforts. In my view, excellent operators have the

following points in common with regard to their

choice and use of guidewire. First, they manipulate the

wires gently. Second, they are patient with the

guidewire once the choice is made and do not give up

easily. In contrast, operators with low success rates

decide too early to step up to the next wire, and I often

encounter cases in which a hard wire has entered the

false lumen. The third point is that these operators

know when to use the Asahi Confianza guidewire fami-

ly (Abbott Vascular). Japanese top operators are careful

about using these wires. Particularly in cases of a very

long CTO lesion, or if there are bends in the occluded

portion, a wire of the Confianza family should not be

used too early. The Miracle series (Abbott Vascular)

is more suited to cope with these types of lesions. It

is important to know the peculiarities of each wire

and use them at the most appropriate occasions.

I N T R AVA S C U L A R U LT R A S O U N D

Intravascular ultrasound (IVUS) is more frequently used

in Japan than in Europe and the US and in cases other

Figure 6. The LAD is occluded at the ostium shown with the arrow (spider view) (A).The LAD distal to the CTO lesion received

good collateral flow from the RCA (RAO view), however, the LAD proximal to the CTO showed a to-and-fro flow, and the exit of

the CTO was not visible (B). Selective angiography of the conus branch using a microcatheter clearly showed the exit of the

CTO (arrow) (spider view) (C).The wire was manipulated under selective angiography of the conus branch (D).

Figure 7. A case of CTO lesion in the proximal RCA (A).The exit of the CTO is near the bifurcation of posterolateral and posterior

descending branch (arrow) (B). Selective angiography of the conus branch having a different orifice than that of the RCA shows

the RCA trunk (arrow) (C). A microcatheter inserted in a diagnostic 6-F internal mammary artery catheter is used for angiogra-

phy of the conus branch. Final angiogram (D).

A B C D

A B C D

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38 I CARDIAC INTERVENTIONS TODAY I OCTOBER/NOVEMBER 2008

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than that of CTO. On a routine basis, we use both angiog-

raphy and IVUS to verify the PCI procedure that we have

performed. In cases of CTO treated with PCI, in particular,

IVUS shows us where and how the guidewire has actually

crossed the lesion. It also shows whether a false lumen

was created. Accumulation of such experience improves

our expertise in manipulation of guidewires.

Being familiar with the everyday use of IVUS makes our

technical wizardry possible to find the entrance to the

CTO with IVUS or to lead the guidewire that entered the

false lumen into the true lumen by IVUS-guided wiring.

M E D I C A L E CO N O M I C S A N D

S O C I A L B AC KG R O U N D

In Japan, PCI for CTO is performed more frequently

than in Europe and the US for other than scientific

reasons. The medical economic situation in Japan is

different from that of Europe and the US. The differ-

ence in insurance systems, in particular, is an impor-

tant factor. In many European countries and the US,

the payment of costs for PCI is made under the

prospective payment system in which the payment

amount for a particular medical service is predeter-

mined and fixed from the beginning. This means that

it is more profitable for the hospital if it performs PCI

procedures with as little device and contrasting agents

as possible. In many countries, doctors are paid more

for the more cases they have in their experience.

Under these circumstances, both hospitals and doc-

tors are happier if they treat a larger number of easier

cases. Difficult cases of CTO that would require longer

hours and more devices for PCI procedures are not

Figure 9. CTO in the proximal LAD (A). The

lesion was of little difficulty because the

length of the occlusion was short and without

bending and calcification. Before the wire

penetrates the exit of the CTO, it is important

to confirm whether the direction of the wire is

correct. In this case, the tip of the wire was

directed too downward in the right anterior

oblique cranial view (left) and too much to the left on the left anterior oblique cranial view (right) (B). Advancing the wire

without correcting the direction would have resulted in entering into the false lumen. The tip of the wire was directed into

the right position on multiple planes and confirmed on cine angiography (C). After penetration of the exit of the CTO, the

right position is confirmed on cine angiography (D). The wire must always be advanced with utmost caution. Final

angiogram (E).

Figure 8. CTO lesion in the proximal RCA (A).The RCA distal to the lesion was not visualized at all with angiography of the LCA

(B).The RCA was clearly visualized by selective angiography of the atrial branch (C). Final angiogram (D).

A

A

D E

B C

B C D

welcome. In Japan, on the contrary, payment for med-

ical services is made on a fee-for-service basis, which

means that the insurance will reimburse all costs for

any device used, and the difference between the

amount reimbursed by the insurance and the actual

amount paid becomes the profit of the hospital.

Furthermore, Japanese doctors are paid fixed salaries

so that the number of PCIs they perform is not reflect-

ed on the amount they receive. In other words, their

income and profit for the hospital do not suffer from

longer hours spent for one case of PCI. This means, in

Japan, the environment is friendlier if you want to use

PCI to treat patients with CTO.

The climate surrounding bypass surgery is also a fac-

tor leading to increased use of PCI for CTO. Although

the success rate of bypass surgery in Japan has

improved, until recently it was not satisfactory; a limit-

ed number of surgeons were achieving good results.

Under these circumstances, before the introduction of

drug-eluting stents, PCI for complicated lesions was

preferred over bypass surgery. Although bypass surgery

has been widely accepted by the general public in

Europe and the US, many Japanese people still shy

away from surgical operations and would rather avoid

them. These social factors lead to increased use of PCI

for CTO in Japan.

CO N C L U S I O N

PCI for CTO is employed more intensively in Japan

than in Europe and the US. While reasons of medical

economics and social background certainly play a role

in this development, we owe this to the top Japanese

operators, although limited in number, who have

achieved high success rates of PCI for CTO. The most

important factors leading to the high success rates are

their efforts in careful interpretation of CAG images

that are taken appropriately before the operation, gen-

tle manipulation of the guidewire and avoidance of

stepping up to other guidewires too easily, and their

daily attitude to never give up and do their best to

overcome the challenges they face. ■

Yasushi Asakura, MD, is Co-Director of

Cardiovascular Medicine, Toyohashi Heart Center in

Japan. He has disclosed that he holds no financial inter-

est in any product or manufacturer mentioned herein.

Dr. Asakura may be reached at +81-532-37-3377;

asakura@heart-center.or.jp.

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